I was wondering about the 4 1/4 inch blocks.
There's no law that says you have to cut multiple layers of fabric, either.
There is a lot of flexibility -
If the blade of your rotary cutter doesn't automatically retract when you put it down, be SURE to do so. Those blades are sharp and blood is so annoying to try to remove from fabric. Also, the cuts tend to bleed profusely.
I strongly recommend prewashing ALL of your fabrics before cutting.
And if you use warm and natural batting, wash and dry that before using, also.
There are others that feel as strongly that you are good to go with the materials straight from the store.